When one of the parameters in your ArcSDE connection changes (i.e. expired password, changed database server, etc.), it would be nice to have an easy way of updating an MXD with the new parameters. If you have a lot of layers in your MXD (a map document to create a web map service could have upwards of a hundred different layers pointing to the same ArcSDE server), opening the MXD in ArcMap can take hours. Even trying to update the connection params via "Set Data Source" in ArcCatalog sometimes hangs.